Nitrogenase FeMoco investigated by spatially resolved anomalous dispersion refinement.
Nitrogenase FeMoco investigated by spatially resolved anomalous dispersion refinement.
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通过空间分辨异常分散细化进行了调查的氮酶femoco。
DOI：
10.1038/ncomms10902
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发表时间：
2016-03-14
影响因子：
16.6
通讯作者：
Einsle O
中科院分区：
文献类型：
--
作者：
Spatzal T;Schlesier J;Burger EM;Sippel D;Zhang L;Andrade SL;Rees DC;Einsle O
固氮酶的[Mo：7 Fe：9 S：C]铁钼辅因子（FeMoco）是已知的最大的金属簇合物，在生物固氮中催化二氮到铵的6电子还原。直到最近它的原子结构才被澄清，而它的反应性和电子结构仍在争论中。在这里，我们表明，其休息S=3/2状态的共同铁氧化态分配必须重新考虑。通过对FeMoco中7个Fe原子的异常散射贡献的空间分辨细化，我们得出结论，三个铁（Fe 1/3/7）比其他四个铁（Fe 2/4/5/6）还原得更多。我们的数据与最近修订的钼离子的氧化态分配一致，提供了FeMoco内的静息态电子分布的第一个空间分辨图片。这可能提供了长期寻求的实验基础，为普遍接受的理论描述的集群，是符合现有的光谱和功能数据。 固氮酶的[Mo：7 Fe：9 S：C]铁钼辅因子（FeMoco）是一个大的金属簇，在生物固氮中具有重要作用。在这里，作者使用铁原子的异常散射贡献的空间分辨细化来确定FeMoco的静态电子分布。
The [Mo:7Fe:9S:C] iron-molybdenum cofactor (FeMoco) of nitrogenase is the largest known metal cluster and catalyses the 6-electron reduction of dinitrogen to ammonium in biological nitrogen fixation. Only recently its atomic structure was clarified, while its reactivity and electronic structure remain under debate. Here we show that for its resting S=3/2 state the common iron oxidation state assignments must be reconsidered. By a spatially resolved refinement of the anomalous scattering contributions of the 7 Fe atoms of FeMoco, we conclude that three irons (Fe1/3/7) are more reduced than the other four (Fe2/4/5/6). Our data are in agreement with the recently revised oxidation state assignment for the molybdenum ion, providing the first spatially resolved picture of the resting-state electron distribution within FeMoco. This might provide the long-sought experimental basis for a generally accepted theoretical description of the cluster that is in line with available spectroscopic and functional data. The [Mo:7Fe:9S:C] iron-molybdenum cofactor (FeMoco) of nitrogenase is a large metal cluster with an important role in biological nitrogen fixation. Here, the authors use spatially resolved refinement of the anomalous scattering contributions of the iron atoms to determine the resting-state electron distribution of FeMoco.